This proposal represents a comprehensive in-depth approach to a common pediatric diagnostic problem, the infant with acute onset of wheezing, in a collaborative research environment. The objectives are to improve current diagnostic capabilities for patients presenting with acute episode of wheezing under 3 years of age and to evaluate the role of and clinical consequences of specific viral infections in this age group. This study proposes to use viral diagnostic studies and selected immunologic studies to expand the "routine" diagnostic evaluation of patients presenting with this problem. Methods used for viral diagnostic studies include attempts at viral serology. Selected immunologic studies include: quantitation of serum immunoglobulins (IgG, IgA, IgM by radialimmunodiffusion and IgE by radioimmunoassay), scratch and intradermal allergy skin testing, and serum radioallergosorbent studies for specific allergens. The utility of each of the proposed viral diagnostic or immunologic studies will be evaluated to determine the potential for improving diagnostic accuracy or prognostic indicators of future onsets of wheezing. The results of viral diagnostic and immunological studies will be compared to a group of infants and small children with pneumonia but no wheezing. This study will add to the current knowledge of the role of specific viral infections in patients with early onset of wheezing during the first three years of life. The results of this study can offer more objective information to clarify the meaning of the diagnostic category of "asthmatic bronchitis" or establish guidelines for its use as a diagnostic term. To date, viral isolations from over 60 patients have been attempted and compared to results of serological studies. BIBLIOGRAPHIC REFERENCE: Betinna, C., Hilman, B.C.: Psychosocial Aspects of Cystic Fibrosis, Maandschr. Kindergeneesk 43: 306-315, 1975.